Magnetic detection device

Abstract

A magnetic detection device is provided in which a first signal is outputted in accordance with the mutual phase relationship between the output of a first magnetoelectric conversion output circuit and the output of a second magnetoelectric conversion output circuit that are based on the movement, in forward direction, of a detection subject, thereby generating a pulse of a high level 1 and a low level 1 ; a second signal is outputted in accordance with the mutual phase relationship between the output of the first magnetoelectric conversion output circuit and the output of the second magnetoelectric conversion output circuit that are based on the movement, in forward direction, of the detection subject; an output signal processing circuit for generating a pulse of a high level 2 and a low level 2 is provided; and not only the pulse of the high level 1 and the low level 1 does not cross the other comparison level, but also the pulse of the high level 2 and the low level 2 does not cross the one comparison level.

1. A magnetic detection device comprising:
 first and second magnetoelectric conversion elements, which are disposed in a biasing magnetic field in such a way as to be in a row along a direction in which a tooth-shaped magnetic moving body as a detection subject moves and to face the tooth-shaped magnetic moving body, for producing changes in electric quantity in accordance with a condition change, in the biasing magnetic field, due to the movement of the detection subject; 
 a first magnetoelectric conversion output circuit for outputting a change in electric quantity produced by the first magnetoelectric conversion element; 
 a second magnetoelectric conversion output circuit for outputting a change in electric quantity produced by the second magnetoelectric conversion element; 
 an output signal processing circuit for outputting a first signal in accordance with a mutual phase relationship between the output of the first magnetoelectric conversion output circuit and the output of the second magnetoelectric conversion output circuit based on the movement, in forward direction, of the detection subject and based on the first signal output and the output of the magnetoelectric conversion output circuit, generating a pulse of a high level  1  and a low level  1  and for outputting a second signal in accordance with the mutual phase relationship between the output of the first magnetoelectric conversion output circuit and the output of the second magnetoelectric conversion output circuit based on the movement, in backward direction, of the detection subject and based on the second signal output and the output of the magnetoelectric conversion output circuit, generating a pulse of a high level  2  and a low level  2  that each are different from at least one of the high level  1  and the low level  1 ; 
 one comparison circuit for comparing a pulse outputted by the output signal processing circuit with one comparison level and outputting the comparison result; and 
 the other comparison circuit for comparing a pulse outputted by the output signal processing circuit with the other comparison level that is different from the one comparison level and outputting the comparison result, 
 wherein the output signal processing circuit is configured in such a way that not only the pulse of the high level  1  and the low level  1  does not cross the other comparison level, but also the pulse of the high level  2  and the low level  2  does not cross the one comparison level. 
 
   
   
     2. The magnetic detection device according to  claim 1 , wherein the output signal processing circuit is configured in such a way as to change the electric potential of the pulse of the high level  1  and the low level  1  or the electric potential of the pulse of the high level  2  and the low level  2  so that not only the pulse of the high level  1  and the low level  1  does not cross the other comparison level, but also the pulse of the high level  2  and the low level  2  does not cross the one comparison level. 
   
   
     3. The magnetic detection device according to  claim 2 , wherein a logic circuit and a transistor are utilized in order to change the electric potential of the pulse of the high level  1  and the low level  1  or the electric potential of the pulse of the high level  2  and the low level  2 . 
   
   
     4. The magnetic detection device according to  claim 1 , wherein the output signal processing circuit is configured in such a way that the electric potentials of the high level  1  and the low level  2  are the same. 
   
   
     5. The magnetic detection device according to  claim 4 , wherein the output signal processing circuit is configured in such a way that the high level  1 ≅ the low level  2 ≅½×(the high level  2 −the low level  1 ). 
   
   
     6. The magnetic detection device according to  claim 1 , wherein the output signal processing circuit includes a first rising-edge D-flip-flop circuit that is triggered by the rising edge of the output signal of the first magnetoelectric conversion output circuit; a second rising-edge D-flip-flop circuit that is triggered by the rising edge of the output signal of the second magnetoelectric conversion output circuit; a first falling-edge D-flip-lop circuit that is triggered by the falling edge of the output signal of the first magnetoelectric conversion output circuit; and a second falling-edge D-flip-flop circuit that is triggered by the falling edge of the output signal of the second magnetoelectric conversion output circuit.